DOWNEY — The housewife-turned-educational activist came before the Downey Board of Education last week with a complaint on behalf of a handicapped student, and they shut her down on a technicality. That was an action they may regret.

Jeanne M. Corbett, who has a handicapped son, is a living nightmare for school officials in Downey and elsewhere in Los Angeles County. She knows the law governing the education of the handicapped like most people know their phone numbers. She is smart. She is irreverent, and she loves a good fight. She vowed to return to the Downey school board.

"I'm the mother from hell," she said, punctuating her observation with a sly smile.

In the past two years, Corbett, 43, has filed reams of complaints with federal and state officials alleging that mentally handicapped students are not receiving an adequate education. As a result, federal education officials recently found that the Los Angeles County Office of Education has been shortchanging hundreds of handicapped students. These students had shorter school days and fewer extracurricular activities than students without handicaps in some areas of Los Angeles County. County officials said they were working to correct the deficiencies.

Federal officials also admonished 31 school districts for failing to ensure that their handicapped students received an adequate education from the county. The county provides special education classes for about 7,000 mentally handicapped students in more than 50 districts.

The woman who caused much of this to happen will confront any school administrator, and has been known to yell to make a point.

She attributes her activism to her Catholic upbringing.

Corbett grew up in a middle-class neighborhood just north of downtown Chicago. Her father was a part-time musician and a full-time machinist. Her mother was a housewife.

Corbett attended Catholic schools and the Sisters of Charity of St. Vincent de Paul imparted a sense of activism in her.

"They had a real commitment to the kids in the neighborhood," Corbett said. "They decided the kids needed a youth center. They went out and raised the money and built one."

Corbett learned about pressure politics growing up with Chicago's Democratic political machine.

Her father was an apartment owner and the local alderman would visit. Corbett called him "Uncle Paddy," and there was never any question that she would register as a Democrat when the time came. It helped "to get building permits and the trash picked up," she said.

Corbett is still a Democrat, but she admits that the sisters probably would blush if they could see her in action today.

Her talk is generously seasoned with profanity, as well as some strained biblical references: "I'm going to go down there and rabble-rouse, make their lives a living hell," Corbett said of an upcoming meeting with some area school officials.

"I give new meaning to the words 'raised by nuns,' " Corbett quipped.

She says her first acts of defiance are recorded in her baby book. "I told my mother if she doesn't do what I want, I'm not going to use her as a mother anymore."

And Corbett recalls creating an uproar while on a summer visit to her grandmother's house in Hot Springs, Ark. She was 10, and racial segregation was the norm in Hot Springs. Corbett wandered to the back of the bus to find a vacant window seat among the black passengers.

A white man came back and offered her his seat near the front of the bus under the pretext that she would be able to hear the bus driver call out her stop. She innocently complied and told the man that he could find an open window seat toward the back of the bus.

"By the time I got to my grandmother's, she had gotten all kinds of phone calls," Corbett said. "It didn't make a damn bit of sense to me."

Corbett said the seeds were sown for her battles with school officials in 1986, when she looked for a good program for her son Robert, 8, who has language and emotional problems.

She visited a couple of county classes for handicapped students and discovered that the school day was shorter than the one for other students.

Corbett has battled continuously with Downey school officials to get them to pay for independent evaluations of her son and to provide the specialized services sometimes required by law. She said she filed complaints against other districts as a matter of conscience.

"If you turn your back and walk, the mess is there for the next person," she said.

But some school officials are suspicious of Corbett's motives. They said she loves the hunt, that she enjoys storming into school offices to yell at her adversaries.